A typical information worker who sits at a computer all day turns to his e-mail program more than 50 times and uses instant messaging 77 times, according to one measure by RescueTime, a company that analyzes computer use habits. The company, which draws its data from 40,000 people who have tracking software on their computers, found that on average the worker also stops at 40 Web sites over the course of the day.

The fractured attention comes at a cost. In the United States, more than $650 million a year in productivity is lost because of unnecessary interruptions, predominately nonurgent digital communication, according to Basex. The firm says that a big chunk of that cost comes from the time it takes people to recover from an interruption and get back to work.

The good news: Companies like Google are committed to doing something about it. How? By putting safeties on their email programs. For example: Email Addict, a new feature Google rolled out last week after figuring out how much time Googlers were wasting using Gmail.